1. Field of the Invention
The present invention relates to an electrical connector assembly for electrically connecting an electronic package such as a central processing unit (CPU) with a circuit substrate such as a printed circuit board (PCB), and particularly to a land grid array connector assembly having a fastening device for securing the CPU therein.
2. Description of Prior Art
FIG. 5 shows a conventional land grid array connector assembly 6 comprising a fastening device 60, and a socket 61 received in the fastening device 60. The fastening device 60 comprises a generally rectangular frame 63, and a lever 62 and a metal clip 64 respectively mounted to opposite sides of the frame 63. The frame 63 defines a pair of locating slots 66 at one side thereof, and a pair of guiding grooves 65 at an opposite side thereof. Each guiding groove 65 is bounded by a first wall 651 and an opposite second wall 652. The lever 62 has a pair of locating portions 623 pivotally received in the locating slots 66 of the frame 63, a driving portion 621 between the locating portions 623, and a handle portion 622 bent perpendicularly from one of the locating portions 623. The clip 64 has a pair of securing portions 641 movably received in the guiding grooves 65 of the frame 63, and a driving hook 644 formed at a free end thereof.
In use, the clip 64 is firstly oriented perpendicular to the frame 63, with the securing portions 641 disposed in the guiding grooves 65 close to the first walls 651. A central processing unit (CPU) 7 is attached on the socket 61, and a copper plate 8 which functions as a heat dissipation device is attached on the CPU 7. Then the clip 64 is rotated down to a horizontal position, with a pair of pressing arms and a pair of pressing pads of the clip 64 abutting the copper plate 8. The handle portion 622 of the lever 62 is rotated down, and the driving portion 621 of the lever 62 engages in the driving hook 644 of the clip 64. The driving portion 621 drives the driving hook 644 down until the clip 64 is in a final pressing position firmly pressing the copper plate 8 on the CPU 7. However, as can be seen from FIG. 6, during rotation of the clip 64, the securing portions 641 may simultaneously move along the guiding grooves 65 toward the second wall 652. When this happens, to the driving hook 644 moves beyond its correct position. As a result, when the handle portion 622 of the lever 62 is rotated, the driving portion 621 of the lever 62 cannot accurately engage in the driving hook 644 of the clip 64 to drive it. This leads to the clip 64 not reaching its correct final pressing position. Thus, the clip 64 fails to properly secure the copper plate 8 on the CPU 7.
In view of the above, a new land grid array connector assembly that overcomes the above-mentioned disadvantages is desired.
Accordingly, an object of the present invention is to provide an electrical connector assembly such as a land grid array (LGA) connector assembly for electrically connecting an electronic package such as a central processing unit (CPU) with a circuit substrate such as a printed circuit board (PCB), whereby the LGA connector assembly has a fastening device for securely and reliably locating the CPU in the LGA connector assembly.
Another object of the present invention is to provide a fastening device for an electrical connector such as a LGA socket to securely and reliably locate an electronic package such as a CPU in the LGA socket.
To achieve the above-mentioned object, a LGA connector assembly in accordance with a preferred embodiment of the present invention is for electrically connecting a CPU with a PCB. The LGA connector assembly comprises a socket and a fastening device surrounding the socket. The fastening device comprises an insulative frame having a first side and a second side opposite to the first side, a cam actuator pivotably mounted to the first side of the frame, and a metal clip pivotably mounted to the second side of the frame.
The clip comprises a plurality of pressing pads, and a post at a free end thereof. The cam actuator comprises a cam and a driver. The cam defines a spiral groove spanning between a circumferential surface of the cam and a center of the cam and facing the clip. The clip is rotated down from a vertical open position to a horizontal closed position, such that the post of the clip is received in the spiral groove of the cam. Movement of the post of the clip toward an end of the frame beyond the cam is limited by a wall of the cam at the spiral groove. Then, the driver is rotated to drive the cam to rotate about a central axis of the cam. The cam drives the post of the clip downwardly, and at the same time the clip moves slightly toward said end of the frame relative to the copper plate. However, excessive such movement in this direction is blocked by said wall of the cam. The handle portion of the driver continues to be rotated until it is locked in a final position. The clip is then at a final pressing position, in which the pressing pads of the clip firmly press down on the copper plate.